Реферат: Sea Turtles Essay Research Paper Lauren McGrorySea
Sea Turtles Essay, Research Paper
Sea turtles have existed since their giant land turtle ancestors returned to the sea sometime during the Age of Dinosaurs. Although there were many species of sea turtles back then, only eight species have managed to survive modern times. The green, black, loggerhead, Kemp s Ridley, olive ridley, hawksbill, flatback, and leatherback turtles are in existence on our planet today. All eight species of sea turtles are listed as threatened or dangered on the U.S. Endangered and Threatened Wildlife and Plants List. It is illegal to harm, or in any way interfere with, a sea turtle of its eggs. (www.geocities.com…seaturtles.html, 2001)
The first turtles appeared 245 to 208 million years ago. Fossil records conclude that the earliest known sea turtles were recorded 208 to 144 million years ago. Most scientists believe that modern sea turtles came from marsh-inhabiting ancestors. (Bustard)
Sea turtles are found in warm and temperate seas throughout the world. Their habitats include shallow, coastal waters, bays, lagoons, and estuaries. Since sea turtles exist all over the world it becomes extremely hard to protect them. (www.seaworld.org…sthabitat.html, 2001)
Migration habits depend on the species of turtle as well as the different populations of the same species in a particular area. While some sea turtles nest and feed in the same general areas, others migrate large distances. Scientists often track migration of the different species of turtles by using the method of flipper tagging. This method allows scientists to obtain information on migration
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destinations but it does not reveal travel routes. (www.seaworld.org…sthabitat.html, 2001)
It is extremely difficult to obtain figures on the populations of sea turtles because most juvenile and male sea turtles don t come ashore to count. The population data is based on the numbers of adult females that come ashore to nest. This method of collecting data is sometimes inaccurate due to the inconsistency of nesting habits among the female populations. Researchers tend to rely more on the changing numbers of nesting females from year to year to determine population trends, rather than trying to obtain exact numbers. They also only consider surveys taken over longer periods of time. (www.seaworld.org…sthabitat.html, 2001)
Humans have an outstanding impact on the endangerment of sea turtles. Sea turtle populations have been seriously reduced worldwide through a number of human influences. The greatest threat to sea turtles is human interference. Many nesting areas all over the world are becoming scarce due to beach development. Threats to the nesting beach in Mexico have cause the population of Kemp s Ridley turtles, the most endangered turtle to date, to decline from 42,000 in 1947 to 1000 by the mid 1980 s (www.environment.about.com…blturt3.htm, 2001) Trash deposited on beaches from humans causes a major problem for sea turtles. Nesting females and hatchlings are disturbed by the presence of trash on nesting beaches. When females that are ready to nest see trash on the beach, they return to the sea instead of nesting. (www.seaworld.org…stlongevity.html, 2001) Some sea turtles
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die from ingesting trash that they mistake for food. Leatherbacks are especially susceptible to ingesting plastic that appears to be a jellyfish. Green turtles eat a wide variety of marine debris such as plastic bags, balloons, and Styrofoam pieces. (http://environment.about.com…blturt1.htm, 2001) Development of beachfronts results in the loss of a dry nesting beach for the loggerhead turtles. (http://environment.about.com…blturt5.htm, 2001) Artificial lighting on beaches has also been known to misrepresent the time of day to turtles that are attempting to nest. Since most turtles are nocturnal nesters, the constant lighting on the beach inhibits them from nesting. (www.seaworld.org…stlongevity.html, 2001) Artificial lighting can cause disorientation of both hatchlings and adults. Leatherback turtles that become disoriented by artificial lighting can wander off into areas away from the beach. This increases their chance of death and injury. (http://environment.about.com…blturt4.htm, 2001) Many beaches are trying to solve this problem by using low-pressure sodium vapor lights that have a lesser effect on the disorientation of the turtles. (www.seaworld.org…stconser.html, 2001)
Another human interference that effects the mortality of sea turtles is hunting. Sea turtles are hunted illegally and legally all over the world. Humans hunt sea turtles for meat, leather, and shells. Humans use sea turtles for things such as combs, eyeglass frames, and food. The greatest threat to the hawksbill is the poaching of its eggs. Because they are of value, many adult females are butchered for the tortoiseshell. (http://environment.about.com…blturt2.htm, 2001).
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The Convention on International Trade in Endangered Species is an international treaty that was developed in 1973 to regulate trade in certain wildlife species. This treaty protects all species of sea turtles. The United States and 115 other countries
have banned the import and export of sea turtle products. (www.seaworld.org…stconser.html, 2001)
Thousands of sea turtles drown in shrimp nets every year. In the Gulf of Mexico, shrimping trawlers are a major contributor in the loss of sea turtles in the area. Because this is such a problem, The National Marine Fisheries Service developed the Turtle Excluder Device that allows shrimp to be caught in the nets but allows turtles to escape to safety before becoming entangled. (Rudlow) Since 1989, the Federal Law requires that the device be installed on the nests of all U.S. fishing trawlers working in areas populated by sea turtles. (www.seaworld.org…stconser.html, 2001)
Although many organizations are working to protect sea turtles, they are unable to undo the damage that has already been done. The sea turtles are declining on our planet at a rapid rate. I became interested in sea turtles when I visited Hawaii this past summer as a member of the Gifted and Talented Science Program. There I was able to take part in the conservation effort by working with the Turtle Rescue Program. While at the beach one day, there was a green turtle washed up on the shore. Although there were signs everywhere on the beach stated how it was illegal to interfere with sea turtles, I watched people try to right before my eyes.
Since human interference is the main cause of the decrease in sea turtle populations world wide, I believe it is our duty to try and correct a mistake that has been repeatedly made. I think that the only way to save the turtles is through awareness and enforcement. I honestly believe that most people who are endangering the lives of the sea turtles are not aware of the problem. They are people simply living their lives without thinking about what animals they are endangering. They may also being living in traditional ways that lead them to believe that it is logical to use animals at their own disposal.
However, I believe that it would be a great loss if sea turtles became extinct. It is the responsibility of countries all over the world, including the United States, to put more time and effort in enforcing laws against the interference of sea turtles. The human race should use the power that they have to save the turtles rather than destroy them.